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PhysicsMediumMCQ2021 · 26 Aug Shift 1

Q16.In a photoelectric experiment, ultraviolet light of wavelength 280 nm is used with lithium cathode having work function ϕ = 2. 5 eV. If the wavelength of incident light is switched to 400 nm, find out the change in the stopping potential. (h = 6. 63 × 10−34 J s, c = 3 × 108 m s−1) JEE Main 2021 (26 Aug Shift 1) JEE Main Previous Year Paper (1) 1. 1 V (2) 0. 6 V (3) 1. 3 V (4) 1. 9 V

What This Question Tests

This question requires applying Einstein's photoelectric equation to calculate the stopping potential for two different wavelengths and then finding the change, involving unit conversions.

Concepts Tested

Einstein's photoelectric equationWork functionStopping potential

Formulas Used

hν = Φ + eV_s

ν = c/λ

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